Scene Manager: LOD switching; Shot Viewer renamed Shot Manager

LODs are child collections of the asset collection (COL_{asset}_LOD{n}).
Overrides hide the other LOD collections (viewport and render), keeping
the rig, pose and animation; collection instances instance the LOD
collection. Each instance has its own LOD, set per instance or for the
selection in the Loaded panel, kept through save, reload and updates.
Loading shows SCENE_MANAGER_DEFAULT_LOD (0).

The Shot Viewer panel is now "Shot Manager" and starts closed. Code
names and SHOT_VIEWER_* config keys are unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dev/make_test_assets.py

@@ -3,8 +3,9 @@
     blender -b --factory-startup --python dev/make_test_assets.py -- <workdir>
 
 bob: a rig (COL_bob: armature + meshes), v001 has 1 mesh, v002 has 2.
-tree: COL_tree, plus an unrelated top-level collection.
-car: COL_car.
+tree: COL_tree holding only LOD collections (COL_tree_LOD0, COL_tree_LOD1), plus an
+unrelated top-level collection. v002 adds a mesh outside the LODs, v003 has no LOD.
+car: a rig, COL_car: armature + COL_car_LOD0..2.
 rock: a single top-level collection not named after the asset (fallback case), its mesh
 using a node group linked from Blender's essentials (an indirect library).
 """
@@ -23,7 +24,7 @@ def mesh_object(name):
     return bpy.data.objects.new(name, mesh)
 
 
-def write(path, collection_name, meshes=1, rig=False, extra=False, node_group=False):
+def write(path, collection_name, meshes=1, rig=False, extra=False, node_group=False, lods=0):
     bpy.ops.wm.read_homefile(use_empty=True)
     scene = bpy.context.scene
     collection = bpy.data.collections.new(collection_name)
@@ -41,6 +42,12 @@ def write(path, collection_name, meshes=1, rig=False, extra=False, node_group=Fa
         ob = mesh_object(f"GEO_{collection_name}_{index}")
         ob.parent = parent
         collection.objects.link(ob)
+    for lod in range(lods):
+        lod_collection = bpy.data.collections.new(f"{collection_name}_LOD{lod}")
+        collection.children.link(lod_collection)
+        ob = mesh_object(f"GEO_{collection_name}_LOD{lod}")
+        ob.parent = parent
+        lod_collection.objects.link(ob)
     if node_group:
         essentials = os.path.join(bpy.utils.system_resource("DATAFILES"), "assets", "nodes", "geometry_nodes_essentials.blend")
         with bpy.data.libraries.load(essentials, link=True) as (_data_from, data_to):
@@ -55,7 +62,9 @@ def write(path, collection_name, meshes=1, rig=False, extra=False, node_group=Fa
 lib = os.path.join(WORKDIR, "lib")
 write(os.path.join(lib, "bob", "v001", "rig.blend"), "COL_bob", meshes=1, rig=True, extra=True)
 write(os.path.join(lib, "bob", "v002", "rig.blend"), "COL_bob", meshes=2, rig=True, extra=True)
-write(os.path.join(lib, "tree", "v001", "model.blend"), "COL_tree", extra=True)
+write(os.path.join(lib, "tree", "v001", "model.blend"), "COL_tree", meshes=0, extra=True, lods=2)
+write(os.path.join(lib, "tree", "v002", "model.blend"), "COL_tree", meshes=1, extra=True, lods=2)
+write(os.path.join(lib, "tree", "v003", "model.blend"), "COL_tree", meshes=1, extra=True)
 write(os.path.join(lib, "rock", "v001", "rock.blend"), "rock_geo", node_group=True)
-write(os.path.join(lib, "car", "v001", "car.blend"), "COL_car")
+write(os.path.join(lib, "car", "v001", "car.blend"), "COL_car", meshes=0, rig=True, lods=3)
 print("Test assets written in", lib)

dev/test_scene_manager.py

@@ -109,7 +109,7 @@ check(
     "chars are posable overrides",
     all(ob.override_library for ob in bpy.data.collections["COL_bob"].all_objects),
 )
-check("shot viewer groups bob as character", "Characters" in shot_viewer.rig_groups(bpy.context.view_layer))
+check("shot manager groups bob as character", "Characters" in shot_viewer.rig_groups(bpy.context.view_layer))
 bpy.ops.wtd_scene.load()
 pump()
 check("load again adds nothing", message().startswith("Nothing new to load"), message())
@@ -129,6 +129,44 @@ bpy.ops.wtd_scene.load(asset_oid=CAR)
 pump()
 check("car loaded once downloaded", loaded().get("car", (None,))[0] == "v001", message())
 
+print("LOD")
+tree_lib, car_lib = bpy.data.libraries["tree"], bpy.data.libraries["car"]
+tree, car = lib.instances(tree_lib)[0], lib.instances(car_lib)[0]
+check("instance shows the default LOD", lib.current_lod(tree_lib, tree) == 0 and tree.instance_collection.name == "COL_tree_LOD0")
+check("override shows the default LOD", lib.current_lod(car_lib, car) == 0)
+hidden = {c.name: (c.hide_viewport, c.hide_render) for c in lib.lods(car_lib, car).values()}
+check(
+    "other LODs hidden (viewport and render)",
+    hidden == {"COL_car_LOD0": (False, False), "COL_car_LOD1": (True, True), "COL_car_LOD2": (True, True)},
+    str(hidden),
+)
+evaluated = {ob.name for ob in bpy.context.evaluated_depsgraph_get().objects}
+check("hidden LODs not evaluated", "GEO_COL_car_LOD0" in evaluated and not evaluated & {"GEO_COL_car_LOD1", "GEO_COL_car_LOD2"})
+bpy.ops.wtd_scene.set_lod(lod=2, library="car", instance=car.name)
+check("override switched to LOD 2", lib.current_lod(car_lib, car) == 2)
+for ob in bpy.context.view_layer.objects:
+    ob.select_set(ob in (tree, bpy.data.objects["RIG_COL_car"]))
+check("LOD of selected", bpy.ops.wtd_scene.set_lod(lod=1, selected=True) == {"FINISHED"})
+check("both switched to LOD 1", (lib.current_lod(tree_lib, tree), lib.current_lod(car_lib, car)) == (1, 1))
+check("missing LOD refused", bpy.ops.wtd_scene.set_lod(lod=5, library="tree", instance="tree") == {"CANCELLED"})
+second = lib.add_instance(scene, bpy.context.view_layer, car_lib)
+check(
+    "second override: LODs found by their linked names",
+    list(lib.lods(car_lib, second)) == [0, 1, 2] and lib.current_lod(car_lib, second) == 0,
+    str([c.name for c in second.children]),
+)
+lib.remove_instance(second)
+lib.update("tree", {"name": "v002", "path": os.path.join(WORKDIR, "lib", "tree", "v002", "model.blend")})
+tree = lib.instances(bpy.data.libraries["tree"])[0]
+check("LOD kept by an update", lib.current_lod(bpy.data.libraries["tree"], tree) == 1)
+check("content outside the LODs: instance refused", bpy.ops.wtd_scene.set_lod(lod=0, library="tree", instance="tree") == {"CANCELLED"})
+lib.update("tree", {"name": "v003", "path": os.path.join(WORKDIR, "lib", "tree", "v003", "model.blend")})
+tree = lib.instances(bpy.data.libraries["tree"])[0]
+check("LODs gone: whole collection instanced", tree.instance_collection.name == "COL_tree" and not lib.lods(bpy.data.libraries["tree"], tree))
+lib.update("tree", {"name": "v001", "path": os.path.join(WORKDIR, "lib", "tree", "v001", "model.blend")})
+tree = lib.instances(bpy.data.libraries["tree"])[0]
+check("LODs back: default LOD", lib.current_lod(bpy.data.libraries["tree"], tree) == 0)
+
 print("Versions")
 check("bob is the latest", sm.version_status(bpy.data.libraries["bob"])[0] == "LATEST")
 fake("/_test/publish", {"file_oid": BOB_FILE, "name": "v003", "available": False})
@@ -217,6 +255,8 @@ bpy.ops.wm.save_as_mainfile(filepath=path)
 bpy.ops.wm.open_mainfile(filepath=path)
 sm._on_load_post()
 check("everything found after reopening", set(loaded()) == {"bob", "car", "lamp", "rock", "tree"})
+car_lib = bpy.data.libraries["car"]
+check("LOD kept after reopening", lib.current_lod(car_lib, lib.instances(car_lib)[0]) == 1)
 sm.connect(bpy.context.scene)
 pump()
 check("versions checked again", sm.version_status(bpy.data.libraries["bob"])[0] == "UPDATE")